Use Latex in Blender
Here is how I would do it


Wrap your expression inside a LaTeX document

\documentclass{standalone}
\usepackage{lmodern} %or whatever you like 
\usepackage[intlimits]{amsmath}
\usepackage{amsthm, amssymb, amsfonts} %Useful stuff
\begin{document}
$ &lt;your expression&gt; $
\end{document}

Pipe that to pdflatex, or save it to expression.tex
If you used a pipe:

pdftocairo -svg texput.pdf expression.svg


If you used a temporary file:

pdftocairo -svg expression.pdf expression.svg

Import expression.svg into blender
Remove temporary files created by pdflatex.


This procedure can be converted into an addon. The dirty way of doing it is to modify the svg importer to run steps 1-3. The correct way is to use Python bidings for Poppler to load the pdf directly.

Test case:

\documentclass{standalone}
\usepackage{lmodern} %or whatever you like 
\usepackage[intlimits]{amsmath}
\usepackage{amsthm, amssymb, amsfonts} %Useful stuff
\begin{document}
$\displaystyle\mathcal{F}\left[f\right](\xi)=\int_{-\infty}^\infty   f(x)\exp(\mathrm{i\xi x})\,\mathrm{d}x$
\end{document}


Result (after some tweeks [curve to mesh, remesh, smooth]: